The invention relates to a metering stopper for the neck of a bottle for the metered delivery of a liquid medium, in which a tubular metering housing is provided which encloses a metering chamber and which has an outlet bore for the medium in its front face and, in the wall, has recesses for the filling of the metering chamber, and a float having a lateral flooding bore is inserted in the metering chamber, the density of which float is greater than that of the medium to be delivered and of which the end facing towards the outlet bore interacts with a valve seat allocated to this outlet bore.
Such a metering appliance is known from German Offenlegungsschrift No. 2,710,626. A float with numerous holes is inserted at the periphery in a cylindrical housing having recesses and a sealing bevel provided for a large pouring opening. A slight bevel is provided on the wall of the float end facing towards the pouring opening, which bevel fits the sealing bevel on the housing. Undoubtedly, by means of the hollow float which can move freely in a flooded metering chamber, the intention here is to block the outflow of the medium to be metered until the metering chamber is filled. However, bubble-free filling, which is essential for accurate metering, is not possible with this known metering appliance. The medium also flows out uncontrolled.
The same applies to other known metering devices. In the metering device described in German Patent Specification No. 1,202,672, a collecting space, a metering space and a receiving space are provided in the metering chamber. The volume of the collecting space is at least as large as the volume of the liquid quantity to be metered, the volume of the metering space is as large as the volume of the liquid quantity to be metered and the volume of the receiving space is at least as large as half the maximum amount of free liquid arising. Although only certain liquid quantities are always delivered from such a device, the metering accuracy leaves something to be desired and considerable differences occur in the liquid quantities actually flowing out.
In German Utility Model No. 7,810,073, a metering stopper is described in which a ball valve is provided which is set in motion by tilting the bottle to and fro and is alternately to open or close the inlet and outlet openings of a metering chamber. Yet even in this embodiment, the metering accuracy is inadequate and very unrelliable.
A further embodiment of a metering device can be gathered from the German Utility Model No. 8,411,429, in which a slide, which can be pushed in axially and has springs provided its periphery, which springs are supported on the metering chamber base, is guided through the metering chamber. In the normal position of the slide, the springs do not sit on the metering chamber base, so that through-flow openings in the metering chamber base are fully open. At the same time, a stopper part coupled to the slide closes an outlet opening of the metering chamber. When the slide is pushed into the metering chamber, the outlet opening is cleared and at the same time the springs come into contact with the metering chamber base and close the through-flow openings. If the slide is only pushed in slightly, a certain part of the through-flow openings remain free, so that an any liquid quantity can be removed from the container. The degree of metering accuracy therefore depends on the manipulation by the user and, moreover, a metering device of several individual parts, some of which must fit very accurately, is required in this embodiment.
In all these known metering devices, the particular disadvantage is the insufficient metering accuracy, and variations of up to almost 75% are measured. At the same time, metering becomes increasingly less accurate the less liquid there is in the bottle or container.
The object of the invention is to create a metering stopper of the type mentioned at the beginning, with which the liquid medium is metered in an exceptionally accurate manner until the bottle is emptied down to the last few drops.
This object is achieved by the metering stopper of the type mentioned at the beginning, when the open end of the metering housing and therefore of the metering chamber, which end is located opposite the outlet bore, is closed by a sealing cap which has a vent bore which, in the assembled metering stopper, is in alignment with the outlet bore of the metering housing, the float consists of a hollow body open on one side and having a cylindrical part and, integrally formed thereon, a tapered cone, the tip of which fits the valve seat as a sealing taper, and a flooding bore is cut out in the wall of the cylindrical part or in the wall of the cone.
Expedient further embodiments of the metering stopper are characterized in the subclaims.